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DNA sequencing is a powerful technique for identifying allelic variation within the human leukocyte antigen (HLA) genes. Sequencing is usually focused on the most polymorphic exons of the class I (HLA-A, -B, -C) and class II (HLA-DR, -DQ, and -DP) genes. These exons encode the antigen recognition site, the region of the HLA molecule that binds peptides and interacts with the T cell receptor for antigen and natural killer cell immunoglobulin-like receptors (KIR). Sanger sequencing of amplified DNA from each HLA gene from a preparation containing one or two alleles yields a sequence that is used to identify the alleles by comparison with a reference database.

DNA sequencing is a powerful technique for identifying allelic variation within the natural killer (NK) cell immunoglobulin-like receptor genes. Because of the relatively large size of the KIR genes, each locus is amplified in two or more overlapping segments. Sanger sequencing of each gene from a preparation containing one or two alleles yields a sequence that is used to identify the alleles by comparison with a reference database.

The human histocompatibility locus, HLA-D, like its counterpart, the murine I region, controls a variety of immune response phenomena including T cell-B cell collaboration, mixed lymphocyte reactions, graft rejection and disease susceptibility (1). In addition, this locus controls the expression of a number of polymorphic antigens, DR, MT/MB/DC and SB (1–3), exhibiting limited tissue distribution. The complexity of the D region antigens has made correlations between structure, genetics and function difficult. Using monoclonal antibodies, two of the polymorphic sets of antigens, SB and DR, have been isolated and compared by amino-terminal amino acid sequencing. The results suggest that the alpha and beta chains of the SB antigens are structurally distinct from the DR alpha and beta chains; however, like the DR antigens, the SB antigens appear to be homologues of the murine I-E antigens.